Die for forging or sharpening the ends of drill rods for rock and like drilling machines



R. A. BEDFORD ,645 FORGING OR SHARPENING THE ENDS OF DRILL R S FOR ROCK AND NG MACHINES Filed Se 5 LIKE DRILLI pt. 19, 19s

. March 29, 1938,

DIE F Jmmm REGINALD ASLINE BEDFORD. .97 W e W Z Patented Mar. 29, 1938 UNITED STATES PATENT ()FFICE Reginald Asline Bedford, Sheffield, England Application September 19, 1935, Serial No. 41,289 In Great Britain January 8, 1935 1 Claim.

This invention relates to the forging of the ends of drill rods for rock and like drilling machines wherein the drill rod end is jumped up by a dolly or former working with a percussive action upon said end in an axial direction.

Hitherto, in forging or sharpening detachable bits for drill rods, it has generally been the practice to form the bit with a longitudinal taper so that it can be retained in position in the dies when being subjected to the percussive blows of the dolly or former and this longitudinal taper has to be formed in a lathe and when the bit is re-sharpened the longitudinal taper has also to be reformed, thus entailing high cost in the forging and sharpening of such drill bits.

It is also the usual custom to transfer the drill bit after being subjected to the action of one set of dies, to the action of another set of dies before the required forged or sharpened end is produced.

The object of this invention is to provide improvements whereby drill bits or drill rods can be expeditiously forged or re-sharpened and at much less cost than hitherto and without the necessity for preforming a tapered end upon them.

According to this invention therefore dies for forging or sharpening the ends of drill rods for rock and like drilling machines comprises companion parts having supporting faces for the drill rod, a plurality of faces forming a plurality of matrices separated one from another by angular walls, said matrices and walls co-acting to sharpen the end of the drill rod with the assistance of endwise percussion upon said drill rod, projections on said angular walls for penetrating the surface of the drill rod in advance of the angular walls and at points radially disposed with respect to the axis of said drill rod whereby to restrain said drill rod against axial displacement.

The invention is applicable to the forging or sharpening of both drill rods having integral ends and drill rods having separate detachable ends.

Referring to the drawing filed herewith:-

Fig. 1 is an elevation of one form of dies made in accordance with this invention and adapted for sharpening drills to a cruciform cutting edge.

Fig. 2 is an end elevation.

Fig. 3 is a plan of a half die; and

Fig. 4 is a cross section on the line AB, Fig. 3;

Fig. 5 is a plan of a half die showing a sharpened drill in position.

a, b are upper and lower dies adapted to be positioned in a suitable machine for closure one against the other and are provided with like die (Cl. Hi-95) faces 0, c at each side of angular walls 0 for forming the longitudinal flutes d of the drill rod e the said angular walls separating matrices ,f, j which are adapted to form the wings g upon the drill when a dolly or former h is operated percussively against the end of the drill rod e, shown as a blank in dotted lines in Fig. 3, the metal of the rod that is displaced by the dolly or former h being forced thereby into the said matrices f, f to form the wings g. The dies are provided with supporting faces 9' for the drill rod when inserted and at a point beyond the part of the drill being actively operated upon.

As will be apparent, when the dolly or former h operates against the drill rod, the latter would be axially displaced unless some means were provided to hold it against such displacement and for this purpose laterally projecting nibs 7c are formed on the angular walls 0 of the four die faces 0, two each being at diametrically opposite points so that when the dies are closed one upon the other over a heated drill rod inserted in the dies the said projecting nibs are caused to bite into the rod, the hot metal of which is somewhat soft, sufliciently to hold it against other than slight axial displacement when the dolly or former is brought into operation. As the forging or sharpening of the rod end takes place, the enlargement of the end eventually assists in preventing displacement.

Where desired, semi-annular ribs m, shown in dotted lines in Fig. 3, may be provided on the supporting faces 7' in addition to the nibs k for circumferentially nipping the drill rod to assist in restraining axial displacement of said drill rod.

What I claim and desire to secure by Letters Patent is:

Dies for forging or sharpening the ends of drill rods for rock and like drilling machines comprising companion parts having supporting faces for the drill rod, a plurality of faces forming a plurality of matrices separated one from another by angular walls, said matrices and walls co-acting to sharpen the end of the drill rod with the assistance of endwise percussion upon said drill rod, projections on said angular walls for penetrating the surface of the drill rod in advance of the angular walls and at points radially disposed with respect to the axis of said drill rod whereby to restrain said drill rod against axial displacement and semi-annular projections on the supporting faces of the companion parts co-acting to circumferentially nip the drill rod.

REGINALD ASLINE BEDFORD. 

